Signal operating altimeter



Sept.V 21, 1943. R. s. GRIER 2,329,715

' SIGNAL OPERATING ALTI-umn Filed Aug. 21. 1941 LIEHT Z4' P@ 5. f3' A u AMPM Fl ER WARNING 1 515mm. [j Z3 INVENTOR Rub-er1.' EJ. Enviar* TTORN EY Patented Sept. 2l, 1943` UNITED STATES PATENT GFFICE 2,329,715 SIGNAL OPERATING ALTIMETER Robert S. Grier, United States Navy Application August 21, 1941, Serial No. 407,773 2 claims. r(o1. 25o-41.5) (Granted under the act amended April 30, 19

This invention relates lto` a signal operating t,

altimeter, `and has for an object to provide an altimeter especially intended for use in a dive bombing airplane, which altimeter is provided with a. warning signal for informing the pilot that he has passed a particular altitude.

A further object of this invention is to provide an altimeter which will warn the pilot, either visually or audibly, or both, that he has reached a particular altitude so that he may know when he should come out of his dive in order lto avoid crashing.

Many fatilities have occurred in dive bombing because of the fact that the pilot is so concentrated on his target that he fails to pull out safely while he still has sufficient altitude to do so. On the other hand. when thepilot has concentrated on pulling out at the proper time he may fail to properly concentrate on his target. With the present invention, however, he may concentrate on his target, knowing that he will'receive ample I preliminary warning, as well as nal warning, as tothe proper time for releasing his bomb on the target and pulling out tosafety.

With the foregoing and other objects in view, the vinvention consists in the construction, combination and arrangementof parts hereinafter described and illustrated in `the drawing, in

Fig. lis an elevational view of one form of altimetergtowhich this invention has been applied, being on line I-I of Fig. 2.

Fig. V2 is a partly schematic, partly sectional view of the altimeter of this invention being on line 2-2 of Fig. 1.

Fig. 3 is a view of an altimeter to which an adjustable form of this invention is applied, being on line 3-3 of Fig. 4; and

Fig. 4 is a partly schematic, partly sectional view on line 4-4 of Fig. 3.

'I'here is shown at I0 an altimeter having the usual altimeter face I I over which is operated the altimeter indicating needles such as the 100 ft. needle I2, suitably geared as at I3 to the 1000 ft. altimeter needle I4, such construction beingany suitable construction as, for instance, that shown in Reissue Pat. 19,079 to Kollsman.

In the form of the invention shown in Figs. 1 and 2, the altimeter is set to operate a preliminary warning signal at 3000 feet altitude, a couple of intermediate warning signals at 2500 and 2000 feet, and a nal warning signal at 1500 feet. The holes I5, I6, II and I 8 are formed through the altimeter face II adjacent the indication marks of March 3, 1883, as 28;'370 0. G. 757) for these respective altitudes. At each of these altitude marks there may be secured a bracket 20 on which. is supported a photocell .2| in proper alignment with itshole, I5, I 5, I1 or I0. Each photocell 2| is connected through a suitable relay or` amplifier 22 to a warning signal 23. This Warning signal may be a buzzer or a bell, or a light so located that it is visible to the free eye of the pilot or may be both an audible and a visual signal. Also, the Warning signal 23 of the respec-r tive altitudes may be of different intensities, the one at 3000 feet, for instance, vbeing just a mild, buzzing sound, while the one at the final altitude of 1500 feet may be a loud, shrieking klaxon or siron, to remind the pilot to pull out without further delay.

A suitable light source 24 directs a beam of light against a reflector 25 so as to reilect the beam 26 through each of the holes I5 to I8 to the photocell 2 I. The 1000 ft. needle I4 is of a width at least equal to the diameter of each of the holes I 5 to I8, so that as it passes over the holes it will intercept the beam 26, thus causing the respective photocell 2| to operate its respective warning signal. I

To prevent accidental operation by the ft.` needle I2, such needle I2 should be suitable narrowed to less than one-half the diameter of the holes I5 to I8, or it may be ol transparent material, or both, so that the passage of the 10o ft. neetue l2 over the holes l5 to la inclusivei will noty suilciently interrupt the light beam 26l to actuate the photocell.

In the form shown in Figs. 3 and 4, instead of placing the holes I5 to I8 in the altimeter face I I, the altimeter face II is provided with a curved slot 21 extending from possibly the 4000 ft. indication to about the 1000 ft. indication. Over this there is placed a segment 28 pivoted about the needle sleeve 30 and provided at its peripheral edge with rack teeth 3l meshing with a gear 32 provided with a control shaft 33. This segment 28 is provided with a plurality of holes I5 to I8 inclusive, so that by rotating the control shaft 33 the holes I5' to I8 inclusive may be placed at the desired altitude indication mark within the limits of the slot 21. The segment 28 is also provided with an annular slot 34 through which the altitude marks are visible, while the photocell brack` ets 20' are mounted on the outer rim 35 of segment 28, the rim 35 having the rack teeth 3| formed in the edge thereof.

The other details and the operation 0f this form are identical with that of the forms of Figs.

further it successively operates the intermediate warning signals and then the nal'warning sig-V nal, if the pilot is still in his dive, to'give-him final Warning that he must pull out with no further delay.

Other medications and changes in the proportions and arrangement of the partsI maybe madeby those skilled in the art Without departing'from the nature of the invention, Within the' scope of what is hereinafter claimed.

The invention described herein may be manufactured and used by or for the Government oi' the United States of America for governmental purposes without the paymenty oi any royalties thereon or therefor. o

Having thus set forth and disclosed the nature oi this invention, what is claimed is:

l. An altitude pressure, responsive control de* vice comprising a sensitive altimeter having a clock face, a pair of indicating needles rotatable over said clock face, one of said needles being rotatable through a greater angular displacement than the other of said needles fora given change in altitude pressure and the Irelative displacement of said needles being ina predetermined ratio, said clock face having indications thereon indicating diierent altitudes, said clock face having at least one aperture. therethrough at4 at; least one. indication thereon corresponding to a predetermined altitude a light source on one,

, side of said clock face, a photoelectric cell on the opposite side of said clock face arranged to receive light from said source through the aperture in theelock face, one of said needles being of a size and material to interrupt the light passing from said light source through said ,aperture to the photoelectric cell; the other of said needles being of' a size or materiai as' not to interrupt the light passing from the light sourcethrough l rotatable through a greater angular displacement than the other of said needles for a given r change in altitude pressure and the relative displacement of said needles Ybeing in a predetermined ratio, said clock face having indications thereonl indicating different altitudes, said clock face having at least one aperture therethrough at at least `one indication thereon,corresponding to a predetermined" altitude, a light source on one side of said clock face, a photoele'ctric cell on the opposite side of said clock face arranged'to re ceive light from said source through the aperture in the clock face, one of said neediesbeing oi a size and material to interrupt the iight passing from said light source through. said aperture to the photoel'ectric cell, the other of said needles being of a size or material as not to interrupt the light passing from the light source through the aperture to the photoelectric cell', an4 eievctric circuit including a control relay operatively oonnected to said cell andr'e'nergized when light-hom said source vthrough saidl vaperture to said' photoelectric cell is interruptedby the presen-ce ofy the needle overI the' ciocl:l lfaceV aperture capable of interrupting the light. source, said clock face aperture beingin the "fornr'roi an arcuate slot extending aboutv a plurality of clock face, Aait'itudx-z indications; a sl'iutter rotatable-Voyer said clock face, said shutter having aplurality angularly displaced apertures Vextending over said clock face slot, there bein-g one photoeiectrfic` cell' for each shutter aperture, ,and means `for adjusting said shutter to bring its apertures into registration with a predetermined selectionrof altitude indications, there being a! separate electric "cir cuit for each photoelectrio cell to be actuated by the interrupting `needle as it extends over the aperture of a particular altitudeindication.

ROBERT C fr'tLEQr'tY.H 

